1. Field of the Invention
The present invention relates to an endoscope that includes a bending portion braking mechanism section which keeps a bending state of a bending portion which is bent, in a bending operation mechanism section which bends the bending portion.
2. Description of the Related Art
Conventionally, endoscopes which are capable of performing observation and various kinds of treatments by inserting elongated insertion portions into bodies have been used. In the endoscopes, some endoscopes include bending portions in insertion portions for the purpose of performing observation by directing observation optical systems contained in distal end portions of the insertion portions to the directions of objects, or for the purpose of facilitating insertion into sites to be examined.
A bending portion includes, for example, a bending portion set configured in such a manner that a plurality of bending pieces are connectively provided rotatably to be bent in two vertical directions or four vertical and lateral directions. Distal ends of bending wires corresponding to the respective bending directions are fixed to a most distal end bending piece of the bending portion set.
According to a configuration, for example, a surgeon pulls a desired bending wire via a bending operation apparatus, and thereby can bend the bending portion in a desired direction. An operation section that is also used as a grasping portion is included at a proximal end side of the insertion portion of an endoscope. A bending operation apparatus is provided in the operation section.
For example, Japanese Patent Application Laid-Open Publication No. 2005-160791 shows an endoscope in which a vertical bending operation lever and a lateral bending operation lever are respectively pivotally supported at both left and right side surfaces of an operation section main body that configures an operation section. In the endoscope, finger rest portions of the respective operation levers extend to a top surface side region of the operation section, and the respective finger rest portions are disposed laterally side by side above the operation section main body.
Further, in the endoscope, a bending lock lever as a bending portion braking mechanism section for keeping a bending state of the bending portion is pivotally supported at both left and right side surface regions of the operation section main body. A finger rest portion of the bending lock lever is disposed on a bottom surface side of the operation section main body which is a region where a forefinger of a grasping hand is naturally located when a surgeon grasps a grip portion with one hand.
Accordingly, the surgeon can properly perform an operation of the vertical bending operation lever which is placed at the operation section main body, an operation of the lateral bending operation lever, or an operation of the bending lock lever with one hand which grasps the operation section.
The bending portion braking mechanism section of the endoscope is configured by including a bending lock lever, a shaft body, a braking regulating plate, a first cam, a second cam, and a friction member. The shaft body is configured to rotate integrally with the bending lock lever. The braking regulating plate is made of a resin with slippage taken into consideration. The first cam is configured by a metal disk which rotates with rotation of the shaft body, and includes a mountain-shaped braking projection portion. The second cam is configured by a metal disk which is disposed without rotating, and includes a mountain-shaped braking projection portion. The friction member is made of a resin, and is moved and pressed against a pulley by the braking projection of the first cam and the braking projection of the second cam being overlaid on each other.
In the bending portion braking mechanism section, a projecting amount of a regulating screw which supports the braking regulating plate is changed, whereby regulation of the braking force of the bending portion braking mechanism section can be performed.
In the endoscopes of recent years, the kind and the amount of the components contained in the endoscopes which are inserted into the insertion portions have increased with high functionality. Therefore, bending force amounts at a time of bending the bending portions become large, and fixing force amounts for keeping the bending states of the bending portions become large.